src/utils/dff.rs

@@ -19,8 +19,9 @@ pub fn ddf(f: Polynomial) -> Vec<(Polynomial, u128)> {
     let mut f_star = f.clone();
 
     let one_cmp = Polynomial::one();
-    while f_star.degree() as u128 >= (d) {
-        let h = Polynomial::x().bpow_mod(q.clone().pow(d), &f_star) + Polynomial::x();
+
+    while f_star.degree() as u128 >= (2 * d) {
+        let h = Polynomial::x().bpow_mod(q.clone().pow(d), f_star.clone()) + Polynomial::x();
 
         let g = gcd(&h, &f_star);
         if g != one_cmp {
@@ -35,9 +36,12 @@ pub fn ddf(f: Polynomial) -> Vec<(Polynomial, u128)> {
 
         d += 1;
     }
+
     if f_star != one_cmp {
         eprintln!("fstar not one");
         z.push((f_star.clone(), f_star.degree() as u128));
+    } else if z.len() == 0 {
+        z.push((f.clone(), 1));
     }
 
     z

src/utils/poly.rs

@@ -25,7 +25,7 @@ impl Polynomial {
     }
 
     pub fn degree(&self) -> usize {
-        self.polynomial.len()
+        self.polynomial.len() - 1
     }
 
     pub fn one() -> Self {